I've read at least half
a dozen different possible explanations for colony
collapse disorder,
but the Apocephalus borealis fly is a new one. This
tiny parasitic fly lays its eggs on honeybees, then the larvae nibble
their way into the bees' brains and eat them alive.
Unsurprisingly, bees
that fall prey to the Apocephalus
borealis flies
don't do so well. The bees get disoriented, abandon their hives,
and become stranded near bright lights.
Although lots of other
problems have been correlated with hives that succumb to colony
collapse disorder, the parasitic fly is unique in that it seems like it
might actually cause the symptoms we see. In addition, the timing
seems right --- in the San Francisco Bay area where the scientists
work, the fly visits honeybees from October to January and again in
late summer, right before the majority of hives come down with colony
collapse disorder.
So far, scientists are
simply adding Apocephalus
borealis to the
suite of problems that colony collapse disorder hives seem to share,
but I wouldn't be surprised if it turns out to be the primary culprit.
For
those of you who didn't take statistics, if two things always happen
together, that's a correlation. For example, Huckleberry likes to
sit in my chair whenever I want to sit there. Just because the
events are correlated, though, doesn't prove anything about causation
--- sometimes, two correlated events are simply caused by the a third
event we didn't think to measure. In my example, the third event
is a warm fire on a cold night --- the warmth attracts both me and
Huckleberry like moths to a flame. Returning to the serious case
of colony collapse disorder, just because we often see Nosema apis and Varroa destructor in the
sick hives doesn't mean these illnesses cause the disorder.